deserialize

Method that can be called to ask implementation to deserialize
json content into the value type this serializer handles.
Returned instance is to be constructed by method itself.

Pre-condition for this method is that the parser points to the
first event that is part of value to deserializer (and which
is never Json 'null' literal, more on this below): for simple
types it may be the only value; and for structured types the
Object start marker.
Post-condition is that the parser will point to the last
event that is part of deserialized value (or in case deserialization
fails, event that was not recognized or usable, which may be
the same event as the one it pointed to upon call).

Note that this method is never called for JSON null literal,
and thus deserializers need (and should) not check for it.